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d2e448d5fd
linux/fs/xfs
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Dave Chinner d2e448d5fd xfs: add CRC protection to remote attributes 
There are two ways of doing this - the first is to add a CRC to the
remote attribute entry in the attribute block. The second is to
treat them similar to the remote symlink, where each fragment has
it's own header and identifies fragment location in the attribute.

The problem with the CRC in the remote attr entry is that we cannot
identify the owner of the metadata from the metadata blocks
themselves, or where the blocks fit into the remote attribute. The
down side to this approach is that we never know when the attribute
has been read from disk or not and so we have to verify it every
time it is read, and we must calculate it during the create
transaction and log it. We do not log CRCs for any other metadata,
and so this creates a unique set of coherency problems that, in
general, are best avoided.

Adding an identifying header to each allocated block allows us to
identify each fragment and where in the attribute it is located. It
enables us to rebuild the remote attribute from just the raw blocks
containing the attribute. It also provides us to do per-block CRCs
verification at IO time rather than during the transaction context
that creates it or every time it is read into a user buffer. Hence
it avoids all the problems that an external, logged CRC has, and
provides all the benefits of self identifying metadata.

The only complexity is that we have to add a header per fragment,
and we don't know how many fragments will be needed prior to
allocations. If we take the symlink example, the header is 56 bytes
and hence for a 4k block size filesystem, in the worst case 16
headers requires 1 extra block for the 64k attribute data. For 512
byte filesystems the worst case is an extra block for every 9
fragments (i.e. 16 extra blocks in the worse case). This will be
very rare and so it's not really a major concern.

Because allocation is done in two steps - the first finds a hole
large enough in the attribute file, the second does the allocation -
we only need to find a hole big enough for a worst case allocation.
We only need to allocate enough extra blocks for number of headers
required by the fragments, and we can calculate that as we go....

Hence it really only makes sense to use the same model as for
symlinks - it doesn't add that much complexity, does not require an
attribute tree format change, and does not require logging
calculated CRC values.

Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Ben Myers <bpm@sgi.com>
Signed-off-by: Ben Myers <bpm@sgi.com>
2013-04-27 12:58:53 -05:00
..
Kconfig fs/xfs: remove depends on CONFIG_EXPERIMENTAL 2013-01-11 11:39:04 -08:00
kmem.c xfs: switch to proper __bitwise type for KM_... flags 2012-05-29 23:28:32 -04:00
kmem.h xfs: switch to proper __bitwise type for KM_... flags 2012-05-29 23:28:32 -04:00
Makefile xfs: split remote attribute code out 2013-04-27 12:49:32 -05:00
mrlock.h xfs: remove subdirectories 2011-08-12 16:21:35 -05:00
time.h xfs: remove subdirectories 2011-08-12 16:21:35 -05:00
uuid.c xfs: remove subdirectories 2011-08-12 16:21:35 -05:00
uuid.h xfs: add CRC infrastructure 2012-11-19 20:11:24 -06:00
xfs_acl.c userns: Pass a userns parameter into posix_acl_to_xattr and posix_acl_from_xattr 2012-09-18 01:01:35 -07:00
xfs_acl.h xfs: Fix build breakage in xfs_iops.c when CONFIG_FS_POSIX_ACL is not set 2011-08-01 02:35:04 -04:00
xfs_ag.h xfs: add CRC checks to the AGI 2013-04-21 14:57:43 -05:00
xfs_alloc_btree.c xfs: add support for large btree blocks 2013-04-21 14:53:46 -05:00
xfs_alloc_btree.h xfs: add support for large btree blocks 2013-04-21 14:53:46 -05:00
xfs_alloc.c xfs: add CRC checks to the AGFL 2013-04-21 14:55:34 -05:00
xfs_alloc.h xfs: convert buffer verifiers to an ops structure. 2012-11-15 21:35:12 -06:00
xfs_aops.c xfs: Fix WARN_ON(delalloc) in xfs_vm_releasepage() 2013-03-22 16:12:37 -05:00
xfs_aops.h Prefix IO_XX flags with XFS_IO_XX to avoid namespace colision. 2012-07-22 11:00:55 -05:00
xfs_attr_leaf.c xfs: split remote attribute code out 2013-04-27 12:49:32 -05:00
xfs_attr_leaf.h xfs: add CRCs to attr leaf blocks 2013-04-27 12:45:01 -05:00
xfs_attr_remote.c xfs: add CRC protection to remote attributes 2013-04-27 12:58:53 -05:00
xfs_attr_remote.h xfs: add CRC protection to remote attributes 2013-04-27 12:58:53 -05:00
xfs_attr_sf.h
xfs_attr.c xfs: split remote attribute code out 2013-04-27 12:49:32 -05:00
xfs_attr.h xfs: split remote attribute code out 2013-04-27 12:49:32 -05:00
xfs_bit.c
xfs_bit.h
xfs_bmap_btree.c xfs: add support for large btree blocks 2013-04-21 14:53:46 -05:00
xfs_bmap_btree.h xfs: add support for large btree blocks 2013-04-21 14:53:46 -05:00
xfs_bmap.c xfs: add CRCs to dir2/da node blocks 2013-04-27 12:33:38 -05:00
xfs_bmap.h xfs: move allocation stack switch up to xfs_bmapi_allocate 2012-10-18 17:42:48 -05:00
xfs_btree.c xfs: add support for large btree blocks 2013-04-21 14:53:46 -05:00
xfs_btree.h xfs: add support for large btree blocks 2013-04-21 14:53:46 -05:00
xfs_buf_item.c xfs: recheck buffer pinned status after push trylock failure 2013-02-14 17:23:42 -06:00
xfs_buf_item.h xfs: add CRC checks to remote symlinks 2013-04-27 11:49:28 -05:00
xfs_buf.c xfs: ensure we capture IO errors correctly 2013-03-14 15:56:53 -05:00
xfs_buf.h xfs: use b_maps[] for discontiguous buffers 2013-01-16 16:07:11 -06:00
xfs_cksum.h xfs: add CRC infrastructure 2012-11-19 20:11:24 -06:00
xfs_da_btree.c xfs: add CRCs to attr leaf blocks 2013-04-27 12:45:01 -05:00
xfs_da_btree.h xfs: add CRCs to attr leaf blocks 2013-04-27 12:45:01 -05:00
xfs_dfrag.c Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2013-02-26 20:16:07 -08:00
xfs_dfrag.h
xfs_dinode.h xfs: add version 3 inode format with CRCs 2013-04-21 15:03:33 -05:00
xfs_dir2_block.c xfs: add CRC checking to dir2 leaf blocks 2013-04-27 12:19:53 -05:00
xfs_dir2_data.c xfs: add CRC checking to dir2 data blocks 2013-04-27 12:00:00 -05:00
xfs_dir2_format.h xfs: shortform directory offsets change for dir3 format 2013-04-27 12:24:32 -05:00
xfs_dir2_leaf.c xfs: add CRC checking to dir2 leaf blocks 2013-04-27 12:19:53 -05:00
xfs_dir2_node.c xfs: add CRCs to dir2/da node blocks 2013-04-27 12:33:38 -05:00
xfs_dir2_priv.h xfs: add CRC checking to dir2 leaf blocks 2013-04-27 12:19:53 -05:00
xfs_dir2_sf.c xfs: shortform directory offsets change for dir3 format 2013-04-27 12:24:32 -05:00
xfs_dir2.c xfs: remove struct xfs_dabuf and infrastructure 2012-07-01 14:50:07 -05:00
xfs_dir2.h xfs: reshuffle dir2 headers 2011-07-13 13:43:48 +02:00
xfs_discard.c xfs: check for possible overflow in xfs_ioc_trim 2012-08-23 14:48:44 -05:00
xfs_discard.h xfs: remove subdirectories 2011-08-12 16:21:35 -05:00
xfs_dquot_item.c xfs: clean up xfs_bit.h includes 2012-05-14 16:21:00 -05:00
xfs_dquot_item.h xfs: remove subdirectories 2011-08-12 16:21:35 -05:00
xfs_dquot.c xfs: add CRC checks for quota blocks 2013-04-21 14:58:22 -05:00
xfs_dquot.h xfs: xfs_dquot prealloc throttling watermarks and low free space 2013-03-22 16:06:30 -05:00
xfs_error.c xfs: increase hexdump output in xfs_corruption_error 2013-04-21 14:48:41 -05:00
xfs_error.h xfs: kill support/debug.[ch] 2011-03-07 10:09:35 +11:00
xfs_export.c fs: encode_fh: return FILEID_INVALID if invalid fid_type 2013-02-26 02:46:10 -05:00
xfs_export.h xfs: remove subdirectories 2011-08-12 16:21:35 -05:00
xfs_extent_busy.c xfs: make xfs_extent_busy_trim not static 2012-05-14 16:21:04 -05:00
xfs_extent_busy.h xfs: make xfs_extent_busy_trim not static 2012-05-14 16:21:04 -05:00
xfs_extfree_item.c xfs: don't free EFIs before the EFDs are committed 2013-04-05 13:25:35 -05:00
xfs_extfree_item.h xfs: don't free EFIs before the EFDs are committed 2013-04-05 13:25:35 -05:00
xfs_file.c xfs: add CRC checking to dir2 data blocks 2013-04-27 12:00:00 -05:00
xfs_filestream.c xfs: rename allocation range fields in struct xfs_bmalloca 2011-10-11 21:15:06 -05:00
xfs_filestream.h
xfs_fs.h xfs: add minimum file size filtering to eofblocks scan 2012-11-08 15:32:29 -06:00
xfs_fsops.c xfs: add CRC checks to the AGI 2013-04-21 14:57:43 -05:00
xfs_fsops.h
xfs_globals.c xfs: add background scanning to clear eofblocks inodes 2012-11-08 15:34:59 -06:00
xfs_ialloc_btree.c xfs: add support for large btree blocks 2013-04-21 14:53:46 -05:00
xfs_ialloc_btree.h xfs: add support for large btree blocks 2013-04-21 14:53:46 -05:00
xfs_ialloc.c xfs: add version 3 inode format with CRCs 2013-04-21 15:03:33 -05:00
xfs_ialloc.h xfs: convert buffer verifiers to an ops structure. 2012-11-15 21:35:12 -06:00
xfs_icache.c xfs: add background scanning to clear eofblocks inodes 2012-11-08 15:34:59 -06:00
xfs_icache.h xfs: add background scanning to clear eofblocks inodes 2012-11-08 15:34:59 -06:00
xfs_inode_item.c xfs: add version 3 inode format with CRCs 2013-04-21 15:03:33 -05:00
xfs_inode_item.h xfs remove the XFS_TRANS_DEBUG routines 2012-12-17 16:29:00 -06:00
xfs_inode.c xfs: add version 3 inode format with CRCs 2013-04-21 15:03:33 -05:00
xfs_inode.h xfs: add version 3 inode format with CRCs 2013-04-21 15:03:33 -05:00
xfs_inum.h xfs: move xfsagino_t to xfs_types.h 2012-05-14 16:20:54 -05:00
xfs_ioctl32.c new helper: file_inode(file) 2013-02-22 23:31:31 -05:00
xfs_ioctl32.h xfs: remove subdirectories 2011-08-12 16:21:35 -05:00
xfs_ioctl.c new helper: file_inode(file) 2013-02-22 23:31:31 -05:00
xfs_ioctl.h xfs: remove subdirectories 2011-08-12 16:21:35 -05:00
xfs_iomap.c xfs: xfs_iomap_prealloc_size() tracepoint 2013-03-22 16:07:56 -05:00
xfs_iomap.h
xfs_iops.c xfs: remove xfs_flush_pages 2012-11-14 15:12:45 -06:00
xfs_iops.h xfs: remove subdirectories 2011-08-12 16:21:35 -05:00
xfs_itable.c xfs: convert buffer verifiers to an ops structure. 2012-11-15 21:35:12 -06:00
xfs_itable.h
xfs_linux.h xfs: Add ratelimited printk for different alert levels 2013-04-03 13:20:39 -05:00
xfs_log_cil.c xfs: Update xfs_log_commit_cil() comments 2013-04-16 13:20:03 -05:00
xfs_log_priv.h xfs: Remove the obsolete XLOG_CIL_HARD_SPACE_LIMIT() macros 2013-04-16 13:18:33 -05:00
xfs_log_recover.c xfs: add CRC checks to remote symlinks 2013-04-27 11:49:28 -05:00
xfs_log_recover.h
xfs_log.c xfs: rename random32() to prandom_u32() 2013-03-07 12:33:57 -06:00
xfs_log.h xfs: xfs_quiesce_attr() should quiesce the log like unmount 2012-10-17 13:39:14 -05:00
xfs_message.c xfs: move xfsagino_t to xfs_types.h 2012-05-14 16:20:54 -05:00
xfs_message.h xfs: Add ratelimited printk for different alert levels 2013-04-03 13:20:39 -05:00
xfs_mount.c xfs: make use of XFS_SB_LOG_RES() at xfs_mount_log_sb() 2013-02-01 14:55:08 -06:00
xfs_mount.h xfs: Remove obsoleted m_inode_shrink from xfs_mount structure 2013-03-14 15:55:32 -05:00
xfs_mru_cache.c xfs: convert to alloc_workqueue() 2011-02-01 11:42:43 +01:00
xfs_mru_cache.h
xfs_qm_bhv.c xfs: Remove boolean_t typedef completely. 2013-01-17 17:32:57 -06:00
xfs_qm_syscalls.c xfs: xfs_dquot prealloc throttling watermarks and low free space 2013-03-22 16:06:30 -05:00
xfs_qm.c xfs: add CRC checks for quota blocks 2013-04-21 14:58:22 -05:00
xfs_qm.h xfs: add CRC checks for quota blocks 2013-04-21 14:58:22 -05:00
xfs_quota_priv.h xfs: use per-filesystem radix trees for dquot lookup 2012-03-14 11:09:06 -05:00
xfs_quota.h xfs: add CRC checks for quota blocks 2013-04-21 14:58:22 -05:00
xfs_quotaops.c userns: Convert qutoactl 2012-09-18 01:01:39 -07:00
xfs_rename.c xfs: move xfsagino_t to xfs_types.h 2012-05-14 16:20:54 -05:00
xfs_rtalloc.c xfs: uncached buffer reads need to return an error 2012-11-15 21:34:05 -06:00
xfs_rtalloc.h xfs: Remove the macro XFS_BUF_PTR 2011-07-25 15:03:13 -05:00
xfs_sb.h xfs: add CRC infrastructure 2012-11-19 20:11:24 -06:00
xfs_stats.c xfs: use common code for quota statistics 2012-03-14 11:09:06 -05:00
xfs_stats.h xfs: use common code for quota statistics 2012-03-14 11:09:06 -05:00
xfs_super.c fs/xfs remove obsolete simple_strto<foo> 2013-01-13 14:42:07 -06:00
xfs_super.h xfs: xfs_sync_data is redundant. 2012-10-17 12:01:25 -05:00
xfs_symlink.c xfs: add CRC checks to remote symlinks 2013-04-27 11:49:28 -05:00
xfs_symlink.h xfs: add CRC checks to remote symlinks 2013-04-27 11:49:28 -05:00
xfs_sysctl.c xfs: add background scanning to clear eofblocks inodes 2012-11-08 15:34:59 -06:00
xfs_sysctl.h xfs: add background scanning to clear eofblocks inodes 2012-11-08 15:34:59 -06:00
xfs_trace.c xfs: add CRCs to dir2/da node blocks 2013-04-27 12:33:38 -05:00
xfs_trace.h xfs: xfs_iomap_prealloc_size() tracepoint 2013-03-22 16:07:56 -05:00
xfs_trans_ail.c xfs remove the XFS_TRANS_DEBUG routines 2012-12-17 16:29:00 -06:00
xfs_trans_buf.c xfs: add version 3 inode format with CRCs 2013-04-21 15:03:33 -05:00
xfs_trans_dquot.c xfs: pass xfs_dquot to xfs_qm_adjust_dqlimits() instead of xfs_disk_dquot_t 2013-03-22 16:05:52 -05:00
xfs_trans_extfree.c xfs: move xfsagino_t to xfs_types.h 2012-05-14 16:20:54 -05:00
xfs_trans_inode.c xfs remove the XFS_TRANS_DEBUG routines 2012-12-17 16:29:00 -06:00
xfs_trans_priv.h xfs: re-enable xfsaild idle mode and fix associated races 2012-07-29 16:27:57 -05:00
xfs_trans_space.h
xfs_trans.c xfs: refactor space log reservation for XFS_TRANS_ATTR_SET 2013-02-01 14:56:31 -06:00
xfs_trans.h xfs: add support for large btree blocks 2013-04-21 14:53:46 -05:00
xfs_types.h xfs: Remove boolean_t typedef completely. 2013-01-17 17:32:57 -06:00
xfs_utils.c xfs: remove the alloc_done argument to xfs_dialloc 2012-07-29 16:00:31 -05:00
xfs_utils.h xfs: propagate umode_t 2012-01-03 22:55:00 -05:00
xfs_vnode.h xfs: remove remaining scraps of struct xfs_iomap 2012-03-15 13:40:16 -05:00
xfs_vnodeops.c xfs: split out symlink code into it's own file. 2013-04-21 15:38:04 -05:00
xfs_vnodeops.h xfs: byte range granularity for XFS_IOC_ZERO_RANGE 2012-11-29 14:21:46 -06:00
xfs_xattr.c xfs: remove subdirectories 2011-08-12 16:21:35 -05:00
xfs.h xfs: don't expect xfs headers to be in subdirectories 2011-08-12 13:57:55 -05:00